Copilot: Reduce excess whitespace and use more of the screen width for responses

The problem
Copilot responses render in a narrow, centered column that uses only about 40% of the page width on a standard desktop display. The remaining space on both sides is empty. Longer outputs, such as account overviews, CTA drafts, and health summaries, require a lot of extra scrolling, which makes them harder to scan and compare.

Proposed solution

• Widen the default response column so it scales with the browser window, while keeping a sensible maximum line length for readability
• Add a user-level toggle (for example, Standard / Wide) to control response width
• Allow the chat history sidebar to be collapsed to free up more room

Why it matters

• Less scrolling when reviewing long account overviews and summaries
• Better readability for lists, scores, and multi-section outputs
• Copilot is increasingly used for work that involves long outputs, so layout efficiency directly affects daily CSM productivity

Who benefits
CSMs and CS Ops users who rely on Copilot for account research, call prep, and CTA workflows, especially on large monitors.